The invention relates to the field of fluid-borne vehicles. In particular, the invention concerns the propulsion of underwater or submersible vehicles using a distributed propulsion system having internal propulsors that add hydraulic energy to a fluid flow internal to the vehicle body, at least two discharge nozzles and at least two backing nozzles that are capable of differential and/or vectored thrust for propelling and maneuvering the vehicle in conjunction with conventional control surfaces and having a wedge-shaped stern configuration which provides an increased volume for the storage of ship systems and stores.
Conventional underwater vehicles typically consist of either an axi-symmetric central body with a propulsion motor shaft exiting a conical projection at the stern on the centerline or two propulsors and shafting systems mounted on either side of the stern of the vehicle. In both arrangements a shaft drives a propeller that provides ship propulsion thrust. These external propeller systems having long propeller shafts, shaft alleys, reduction gears, and other mechanical support systems are large and expensive.
Conventional underwater vehicles also include jet type propulsion systems. For example, Lehmann (U.S. Pat. No. 3,182,623) discloses a structure for submarine jet propulsion, Wislicenus et al. (U.S. Pat. No. 3,575,127) disclose a vehicle propulsion system for fluid-submerged bodies, such as torpedoes or submarines, and Meyers et al. (U.S. Pat. No. 5,574,246) disclose an underwater vehicle having an improved jet pump propulsion configuration. Each of these jet type propulsion systems basically includes a motor driven pump located inside the vehicle with water being taken in, pressurized, and pumped out near the aft end of the vehicle to form the jet pump propulsion unit. However, these conventional jet type propulsion systems experience limitations with maneuvering the vehicle through the water and with stopping or reversing the vehicle.
For example, Sinko et al. (U.S. Pat. No. 6,217,399 B1) disclose a propulsion arrangement for axi-symmetric fluid-borne vehicles having four propulsion modules that are separate from and external to the hull of the vehicle and that are removably mounted at the rear of the vehicle. The four propulsion modules are in symmetric disposition about the vehicle axis and control vanes are mounted on the module housing at locations between the propulsion modules. However, the propulsion arrangement disclosed by Sinko et al. only provides a rearward discharge of fluid driven by a rotating blade section for the forward movement of the vehicle. As shown, this arrangement does not provide for vectored thrust.
Control surfaces and projections are typically positioned forward of the propeller or jet propulsor. Hence, flow distortions flowing along the exterior of the vehicle in the form of wakes enter the propeller/propulsor causing vibration and/or cavitation. Also, the flow deflected by the control surfaces in a turn is partially re-aligned with the vehicle centerline reducing the effectiveness of the control surfaces. Additional projections/appendages from the axi-symmetric central hull shed wakes that enter the external propeller(s), and cause additional vibration.
Typically, these conventional external propeller systems and conventional jet propulsion units are not capable of differential and/or vectored thrust and therefore require a relatively large turning radius relative to the length of the vehicle. This makes operating in shallow water and tight areas, such as along coastlines and harbors, difficult.
The conical tapered aft section in these conventional vehicles house the shafting and shaft alley for the shaft driven propeller. Accordingly, this conical tapered aft section typically does not provide sufficient space for the storage of wet or dry stores.
The conical shaped aft section of conventional underwater vehicle also make it difficult to access the after most portion of the stern section and also makes it difficult to store and deploy items, such as weapons, sensors, other vehicles, swimmers, and the like, due to the shafting extending through the stern section and the location of the external rotating propellers.
In addition, some conventional vehicles include integrated power distribution arrangements. For example, U.S. Pat. No. 6,188,139 B1, entitled Integrated Marine Power Distribution Arrangement, issued to Thaxton et al., discloses a marine power distribution arrangement including a turbine-driven AC generator which supplies power through a switchgear unit to a transformer and power converter(s) for ship propulsion and ship service loads. However, conventional integrated electric plants typically have the propulsion components located in the primary pressure hull with a shaft or shafts extending through the hull to the external propeller(s) and therefore lack flexibility in the arrangement of the components.
Therefore a need exists for improved propulsion system for an underwater vehicle having differential and/or vectored thrust that provides for forward and reverse propulsion and full maneuverability of the underwater vehicle. The need also exists for an underwater vehicle having a stern configuration that provides an increased volume in the stem section for increased wet and/or dry storage.
The present invention is directed to an underwater vehicle including an elongated body having a bow, a forward section, a mid-section, an aft section, and a stern. At least one inlet opening in the body for receiving a fluid from an external fluid operating environment into the body. Inlet ducting is connected to the at least one inlet opening, the inlet ducting containing and guiding the fluid as it flows internal to the body. At least one propulsion pump connected to the second end of the inlet ducting, the at least one propulsion pump adding hydraulic energy to the fluid to induce a flow of the fluid though the body. Outlet ducting having a first end and a second end, the first end connected to the at least one propulsion pump, the outlet ducting containing and guiding the fluid as it flows internal to the body. At least two discharge nozzles connected to the second end of the outlet ducting at the aft section, the at least two discharge nozzles positioned in a laterally spaced apart relationship along a horizontal beam of the body on opposite sides of a longitudinal centerline axis.
The number and exact location of the inlet duct, pumps, discharge nozzles, controlling surfaces, etc. can be varied by a person of ordinary skill in the art to meet common design specifications.
The at least two discharge nozzles provide propulsive thrust to propel the vehicle through the fluid operating environment. In addition, the at least two discharge nozzles are capable of producing one or more of a differential thrust and a vectored thrust to maneuver the vehicle through the fluid operating environment.
Differential thrust may be provided by changing the volume of fluid flowing to each of the at least two discharge nozzles. The at least two propulsion pumps each having a variable speed power source for driving each of the at least two propulsion pumps at differential speeds can be used to drive a differential flow of fluid to the at least two laterally spaced apart discharge nozzles that produce differential thrust to propel and maneuver the vehicle through the fluid operating environment. Alternatively, a diverter plate can be used, with one or more pumps, to divert a portion of the fluid flowing to the at least two discharge nozzles.
Vectored thrust may be provided by changing the discharge angle from the longitudinal centerline at which the fluid flow exiting each of the at least two discharge nozzles. During normal ahead operations, the discharge nozzles discharge a fluid flow in a normally rearward direction to propel the vehicle in a forward direction. During maneuvering, the discharge nozzles can be moved, preferably in multiple degrees of freedom, to produce vectored thrust.
Preferably, the discharge angle of the fluid flow exiting the discharge nozzles is vectorable in at least two directions including a horizontal direction and a vertical direction to produce a vectored thrust in a yaw plane for turning to port and starboard and a pitch plane for diving and ascending. In addition, the discharge nozzles are preferably independently vectorable allowing independent selection of thrust vectoring at least two directions to further control yaw, pitch, and roll of the vehicle.
A vectored thrust actuator system can be used to move each of the discharge nozzles. According to one embodiment of the invention, the vectored thrust actuator system can include at least one yaw actuator coupled to one side of each of the discharge nozzles for moving the discharge nozzle in a horizontal plane and at least one pitch actuator couple to one of a top and bottom of each of the discharge nozzles for moving the discharge nozzle in a vertical plane. Other means of altering the discharge angles of the discharge nozzles, such as flexible couplings, movable vanes, a variable geometry or articulated nozzle, etc. can be used.
According to another aspect of the invention, the underwater vehicle of claim 1 further includes a backing, reversing, and stopping capability. At least two backing nozzles that are selectively fluidly connected to an outlet of one or more of the at least one propulsion pumps for producing a backing thrust to slow a forward motion of the vehicle and to propel the vehicle generally in a backward axial direction.
The backing nozzles discharge a flow of fluid in a normal direction that is generally forward toward the forward section and wherein the backing nozzles are preferably vectorable in at least two directions comprising a fore and athwartship direction and a vertical direction to produce a vectored thrust to further assist with propelling and maneuvering the vehicle. Preferably, the backing nozzles are independently vectorable in the at least two directions to control yaw, pitch, and roll of the vehicle.
A backing door can be provided for selectively diverting a flow of the fluid exiting the propulsion pump to one of the discharge nozzles and the backing nozzles. A backing door actuator system moves the backing door between a first position where flow to the backing nozzles is closed off and a second position where flow is diverted to a backing duct that guides the fluid to the backing nozzles. The backing door can be moved between a first position wherein the flow diverter device closes off the backing ducting and the flow of fluid exiting the propulsion pump flows to the discharge nozzles, and a second position wherein the flow diverter device opens the backing ducting and the flow of fluid exiting the fluid propulsor flows to the backing nozzles.
Preferably, the inlet openings are positioned in the body to minimize or exclude one or more of surface and bottom debris, air, and turbulence resulting from external protrusions from the body from entering the inlet openings.
According to one aspect of the invention, the at least one inlet opening includes two partial annular inlet openings positioned symmetrically with one partial annular inlet opening on a port side and one partial annular inlet opening a starboard side of a forward end of the aft section. According to another aspect of the invention, the at least one inlet opening comprises a partial annular inlet opening that extends over approximately three quarters of a circumference of the body from the port side across a bottom to the starboard side.
The underwater vehicle of claim 1, wherein each of the at least one propulsion pump comprises a double suction mixed flow pump having a motor directly coupled and adjacent to the pump.
A pair of faired discharge ducts extending outward and rearward from the aft section of the body can be used to house the discharge nozzles. Also, a portion of the outlet ducting can extend through each faired discharge duct to the discharge nozzles located at a distal end of each of the faired discharge ducts.
Furthermore, the underwater vehicle can include one or more control surfaces to farther facilitate maneuverability of the vehicle. For example, the vehicle can include one or more vertical control surfaces extending in a vertical plane from the aft section and/or one or more horizontal control surfaces extending in a horizontal plane from the aft section. Vertical control surfaces further facilitate maneuvering of the vehicle on a yaw plane and horizontal control surface further facilitate maneuvering of the vehicle on a pitch plane.
In accordance with another aspect of the invention, the underwater vehicle can further include a secondary thrust-driven propulsion system. The secondary thrust-driven propulsion system includes at least one secondary inlet opening in the body, secondary inlet ducting connected to the secondary inlet opening for guiding a flow of fluid therethrough, at least one secondary propulsion pump connected to the secondary inlet ducting for adding hydraulic energy to a fluid to drive the fluid through the secondary thrust-driven propulsion system, secondary outlet ducting connected to the secondary propulsion pump for guiding a flow of fluid therethrough, and at least two secondary discharge nozzles connected to the bow outlet ducting for discharging the fluid being driven by the at least one secondary propulsion pump. The at least two secondary discharge nozzles are disposed in a laterally spaced apart relationship with one secondary discharge nozzle being position on a port side of the vehicle body and one secondary discharge nozzle being positioned on a starboard side of the vehicle body. The secondary thrust-driven propulsion system can be used to produce one or more of a differential thrust and a vectored thrust to further assist in propelling and/or maneuvering the vehicle.
According to another aspect of the present invention, the underwater vehicle can include a distributed power generation, distribution, and control system for providing power to and control of the thrust-driven propulsion system. The distributed power generation, distribution, and control system includes at least one power source located in a primary pressure hull of the body, a plurality of turbo-generators located in a primary pressure hull of the body for converting a power output from the power source to electrical energy, controllers and a bus system located in a primary pressure hull of the body for controlling the distribution of electrical energy, at least one propulsion driver located in either the primary pressure hull or a fairing extending aft from the primary pressure hull at the aft section of the body, and at least one propulsion pump located in the fairing, the at least one propulsion pump being coupled to the at least one propulsion driver. This type of propulsion system having distributed, modular components results in the flexible arrangement and interconnectability of the power generation, distribution, and control.
The present invention is also directed to an underwater vehicle having a wedge shaped stern configuration. The underwater vehicle includes a bow, a stem, an ellipsoidal bow section, a cylindrical central section, and a wedge shaped fairing. The wedge shaped fairing includes a substantially constant width and tapering smoothly from a first cylindrical end connected to the central section to a second end forming a horizontal edge at the aft distal end of the body. The wedge shaped stern section defining a space having an increased volume at the stern for housing additional ship systems and stores.
The wedge shaped fairing further includes an upper tapered surface, a lower tapered surface, port and starboard sidewalls, and the horizontal edge. The upper tapered surface tapers downward heading aft from the first end to the second end. The lower tapered surface that tapers upward heading aft from the first end to the second end. The port and starboard sidewalls are disposed between and connect the upper tapered surface to the lower tapered surface. The horizontal edge is formed along a horizontal beam where the upper tapered surface to the lower tapered surface meet at the aft distal end of the body.
In addition, one or more trunks or passageways can be provided extending through the space defined by the wedge-shaped fairing. Preferably, the trunk(s) are pressurized from a primary pressure hull of the vehicle. The trunk includes an opening between the trunk and a fluid operating environment in which the vehicle operates. A trunk door covers the opening and selectively opens and closes the trunk opening in order to dispense and/or retrieve devices from the stern of the vehicle.
The underwater vehicle having a wedge shaped fairing can include a thrust-driven propulsion system as described above. Preferably, the propulsion pumps, outlet ducting, and at least two discharge nozzles are located in the space defined by the wedge shaped fairing. In addition, one or more of a control system and an actuator system may be located in the trunk.
The underwater vehicle having a thrust-driven propulsion system can include two or more alternative stern configurations. In a first exemplary embodiment, the underwater vehicle can include a stern configuration including a tapered aft conical stern section having at least two faired discharge ducts that extend outward and rearward from the stern section and include portions of the outlet ducts and the discharge nozzles. The faired discharge ducts allow the discharge nozzles to be positioned in a laterally spaced apart relationship on opposite side of the longitudinal axis of the vehicle.
In a second exemplary embodiment, the underwater vehicle can include a stern configuration including a wedge shaped fairing that provides a space and covering in which portions of the thrust-driven propulsion system, including the at least two discharge nozzles, can be positioned.
The present invention is also directed to a method for propelling and maneuvering an underwater vehicle through a fluid operating environment. The method includes providing a body having an ellipsoidal shaped bow section, a cylindrical mid-ship section, and a stern section; ingesting fluid from the operating environment into the body through one or more inlet openings; guiding the fluid through the body through internal ducts; driving the fluid through the ducts using one or more pumps to add hydraulic energy to the fluid passing through the ducts; propelling the body through the fluid operating environment by discharging the fluid exiting from the pumps through at least two discharge nozzles positioned at the stern section in a laterally spaced apart relationship along a horizontal beam on opposite side of a longitudinal centerline of the body; and maneuvering the body through the fluid operating environment by controlling one of a magnitude and a direction of the fluid being discharged from the body thereby producing one or more of a differential and a vectored thrust.
In accordance with another aspect of the invention, the method further includes varying the speed of a power source used to drive the pumps to produce differential thrust for controlling one or more of yaw, pitch, and roll of the vehicle.
In accordance with another aspect of the invention, the method further includes moving the discharge nozzles in at least two dimensions to produce vectored thrust in multiple degrees of freedom for controlling one or more of yaw, pitch, and roll of the vehicle.
The method can further include diverting the fluid exiting the one or more pumps to at least two backing nozzles positioned at the stern section in a laterally spaced apart relationship with at least one backing nozzle being positioned along a port side and at least one backing nozzle being positioned along a starboard side of the body to provide a backing thrust; reversing and/or stopping the body by discharging the fluid exiting from the pumps through at least two backing nozzles; and maneuvering the body through the fluid operating environment by controlling one of a magnitude and a direction of the fluid being discharged from the body thereby producing one or more of a differential and a vectored thrust.
Furthermore, the method can include providing a secondary thrust-driven propulsion system in the bow section of the body; ingesting fluid through at least one secondary inlet opening in the body; driving the ingested fluid using one or more secondary pumps connected to the secondary inlet ducting; discharging the driven fluid through at least two secondary discharge nozzles connected to the secondary pumps to produce a secondary thrust, the at least two secondary discharge nozzles being disposed in a laterally spaced apart relationship with one secondary discharge nozzle being position on a port side of the vehicle body and one secondary discharge nozzle being positioned on a starboard side of the vehicle body; and producing one or more of a differential thrust and a vectored thrust by controlling a magnitude and a direction of the fluid flow being discharged through the secondary discharge nozzles.
Additional features of the present invention are set forth below.